Increased disk utilization and queue size in accounting data after updating to kernel-3.10.0-1160.15.2.el7

Solution Unverified - Updated -

Issue

  • Increased disk utilization and queue size after updating to kernel-3.10.0-1160.15.2.el7
  • Issue does not show on kernels prior to kernel-3.10.0-1160.15.2.el7 (note, patch was actually done in kernel-3.10.0-1160.13.1.el7, but that was not released)
  • Issue is only shown by an increase in the accounting numbers; no actual performance issue exists.
    • Evident when comparing prior kernel accounting data to new kernel accounting data
  • For example, note the increased %util on similar operations:
kernel-3.10.0-1160.11.1.el7
===========================
11:50:01 AM       DEV       tps  rd_sec/s  wr_sec/s  avgrq-sz  avgqu-sz     await     svctm     %util
Average:     dev259-0   1330.84   8635.72  43590.53     39.24      0.53      0.39      0.04      5.93
Average:     dev259-1   1336.13   8582.11  43758.02     39.17     12.77      9.32      0.04      5.99
Average:     dev259-6   1364.61   9004.60  43878.10     38.75      0.43      0.31      0.04      6.12
Average:     dev259-9   1365.20   9010.97  44383.64     39.11      1.87      1.35      0.04      6.01
Average:    dev259-12   1357.83   8800.33  44060.89     38.93      2.85      2.05      0.04      6.04
Average:    dev259-13   1360.67   9387.25  43672.18     39.00      0.51      0.37      0.05      6.15

kernel-3.10.0-1160.21.1.el7
===========================
11:50:01 AM       DEV       tps  rd_sec/s  wr_sec/s  avgrq-sz  avgqu-sz     await     svctm     %util
Average:     dev259-0   1863.29   7101.66  54567.36     33.10      8.84      4.74      0.10     18.18
Average:     dev259-4   1832.84   6809.61  54489.68     33.45      5.35      2.92      0.09     17.06
Average:     dev259-3   1825.97   6825.86  54364.51     33.51      4.68      2.56      0.09     16.98
Average:     dev259-9   1889.48   7099.16  55319.70     33.04      9.77      5.17      0.09     17.07
Average:    dev259-10   1860.63   6895.86  54649.01     33.08     10.55      5.67      0.09     16.85
Average:    dev259-11   1873.74   7405.25  54449.48     33.01      6.71      3.58      0.10     18.01

Environment

  • Red Hat Enterprise Linux 7
  • kernel-3.10.0-1160.15.2.el7 or newer

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